NEWS for North Dakotans
Agriculture Communication, North Dakota State
University
7 Morrill Hall, Fargo, ND 58105-5655
January 8, 1998
Because top-quality forages may be in short supply in some areas of the state, dairy producers are using more corn silage than normal this winter, notes a North Dakota State University dairy specialist. And that requires some adjustments in management.
"If corn silage is going to dominate the milking ration without or with only a small amount of hay or haylage, then properly balancing rations based on forage neutral detergent fiber, total neutral detergent fiber, and particle size distribution will be critical," says J.W. Schroeder of the NDSU Extension Service.
One option to consider for balancing rations are byproducts from the region's agricultural processing industry, he says. Byproducts that complement a heavy corn silage ration and that help balance fiber are corn gluten feed, wheat midds, soyhulls, and cottonseed.
"Particle size of corn silage will be important to help maintain good digestibility and normal rumen function," Schroeder says. Research at Pennsylvania State University indicates that when corn silage makes up a greater proportion of the ration, it is recommended to have 5 to 10 percent of the particles greater than 0.75 inch, 40 to 50 percent of the particles between 0.75 and 0.31 inch, and 40 to 50 percent of the particles less than 0.31 inch. Corn silage that is chopped and rolled should have between 10 to 15 percent of the particles greater than 0.75 inch.
Because corn silage normally contains about 8 to 9 percent crude protein, supplemental protein should be added to compensate for protein normally contained in hay and haylage. Ideal protein ingredients include both soy- and animal-based sources. Also, Schroeder notes, a non-protein nitrogen source, like feed-grade urea, can work well in corn silage diets. However, if appreciable amounts of urea are fed in the milk cow diet, some urea should be included in dry cow diets as they approach calving to allow them to become acclimated to the feed ingredient and minimize off-feed problems when they move onto lactation diets. If urea is included in the diet at substantial levels, maintain adequate sulfur levels in the diet and include a buffer in the ration at a rate of 0.8 percent on a total ration dry matter basis.
Schoeder lists other considerations for managing dairy cows on rations high in silage:
"To make the most of short feed supplies, producers need to inventory their available feeds and test forages and other feed ingredients so that accurate rations can be formulated," he says.
"Forages are of utmost importance in the dairy diet," Schroeders says, "but they are more variable in nutrient content than feed grains. If representative samples from different fields were taken and tested as the harvest season progressed, that nutrient information can be used to best manage available feed supplies."
Silages should be tested for dry matter, crude protein, soluble and degradable protein, acid detergent fiber, neutral detergent fiber, ash, and minerals (calcium and phosphorus, at the minimum).
For a list of forage testing labs, call your county office of the NDSU Extension Service. For a list of some of the byproducts available in North Dakota, visit the World Wide Web at www.ag.ndsu.nodak.edu/aginfo/dairy. Click on the title, "Partial List of North Dakota Coproduct Prices."
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Source: J.W. Schroeder (701) 231-7663
Editor: Tom Jirik (701) 231-9629